[java] UTF-8 text is garbled when form is posted as multipart/form-data

I'm using org.apache.commons.fileupload.servlet.ServletFileUpload.ServletFileUpload(FileItemFactory) and defining the encoding when reading out parameter value:

List<FileItem> items = new ServletFileUpload(new DiskFileItemFactory()).parseRequest(request);

for (FileItem item : items) {
    String fieldName = item.getFieldName();

    if (item.isFormField()) {
        String fieldValue = item.getString("UTF-8"); // <-- HERE